Any updates on when this is likely to work? Have just acquired full version of Veeam specifically for new ESXI 6.5 Build, and reseller failed to mention non-supported scenario. Am getting NFC errors all over the place...

We now have the Release Candidate build of Update 1, so those of you anxious to test Veeam Backup & Replication 9.5 against vSphere 6.5 are welcome to contact our support to get the supported pre-release code and participate in the pilot. Thanks!

Please note however that we stopped publishing complete "fix lists" for updates a couple of years ago, since it became too time-consuming to compile this list from R&D records with a few hundreds of bugs fixed in every update. However, support has access to the internal R&D bug tracker and can advise whether the specific bug submitted through a support case was fixed.

That said, we do document full list of all new features and enhancements, as well as areas of major stability and reliability improvements which are important for customers to be aware of (here's a sample for level of details). We will have the same document ready in time for U1 GA in a few weeks, When It's Ready™

Just an update...I reached out to support via a My Veeam web ticket asking to pilot the RC. Within 5 minutes, they sent me a link to download the RC for Update 1. They did say, however, that I cannot post the link to the download here, as they need to be able to track downloads to tickets, etc. I'll be testing out in lab with vSphere 6.5 and Nimble, and will post results with latest VM hardware profiles, etc.

Another update. The RC successfully installed and now allows me to add the 6.5 vCenter server, and access the 6.5 ESXi hosts. It immediately errored out before by saying the vcenter server version was not supported. I will say, however, that it took over 30 minutes to install on a Windows 2012 R2 based VM inside VMware Workstation, the VM having quad procs, 16gb ram, and running off SSDs. YMMV.

Onsite Backups
Onsite Windows 2012R2 VM running veeam 9.5 with the RC for U1. (Using Direct SAN access)
Veeam is connecting to the vCenter 6.5 VM
Successfully backed up 30 x Windows 2012 R2 VM's, including Exchange, AD, SQL, RDS, IIS, and various app servers.
Backups go to a CIFS share (60tb running on a Synology NAS)
I have done a full VM Restore (inc registration) to an alternate ESXi 6.5 host in an isolated network, they were a DC, SQL and App server.
I have power on the restored VM's and Veeam successfully took AD out of safe mode and auto rebooted, SQL and APP servers were fine.

Offsite Replication
I have an offsite Windows 2012R2 VM running veeam 9.5 with the RC for U1. (this uses a separate local proxy running 9.5 with RC for U1 also) (Using NBD access)
Veeam is connecting to the vCenter 6.5 VM
I have successfully replicated 14 x Windows 2012R2 VM's Exchange, AD, SQL, IIS, and an IP PBX.
I am replicating from both ESX 5.5 and 6.5 hosts to only ESX5.5 hosts at offsite location
These were seeded by replicas that were originally replicated by Veeam 8.0.0.2084 connected to vCenter 5.5 U3
I have powered on the Replicas and Veeam successfully took AD out of safe mode and auto rebooted, SQL and APP servers were fine.

I will now move to backup and replicate all VM's and continue testing!

Thanks for all this detailed information. It is appreciated. Keep it coming . Please do let us know if you encounter issues and work with support asap so we can get those fixed in the final U1 release.